Nonvolatile memory devices are capable of storing data for extended periods of time without needing to be powered to maintain such data storage. Information is written to a solid state memory device, such as a flash memory device, by changing the electrical characteristics of transistor-based memory cells to change how such memory cells react to applied voltages. The electrical characteristics of different memory cells in a solid state memory device are representative of binary bits that can be read by sensing output voltages of the memory cells in response to applied input voltages.
When data is to be erased or overwritten in a flash memory device, an erase command is issued to the flash memory device by a memory host controller. To perform an erase operation, the flash memory device must generate large voltages to apply to the target memory cells to be erased. In addition, the voltages must be applied to the target memory cells over a particular duration to ensure that the electrical characteristics of the memory cells are changed to reflect an erased state. Such voltage generation and voltage application require a significant amount of time that makes an erase operation longer than other memory access operations.
The figures are not to scale. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts.